Why your balance is really a strength problem

Somebody wobbles. The instinct, in a gym and in a clinic alike, is to give them balance work. Stand on one leg. Close your eyes. Get on the cushion. It feels like the obvious answer, because the problem announced itself as a balance problem.

It is often a strength problem wearing a disguise.

What they actually measured

Researchers at Inonu University in Turkey, publishing in Applied Sciences in 2022, took 33 healthy young men, average age 21, and put them through two tests that are not usually thought of as related.

The first was the Y Balance Test. You stand on one leg and reach as far as you can with the other foot in three directions: straight ahead, then back and inward, then back and outward. You do not get to touch down for support. The reach distances are normalized to your leg length, then averaged into a single composite score. It is a standard tool for spotting side to side asymmetries and for predicting lower limb injury risk.

The second was a one repetition maximum leg extension, one leg at a time, on the same side they had just tested for balance. The heaviest single load the knee could straighten against.

Then they looked at whether the two tracked each other.

They tracked each other closely

The other directions followed the same pattern, less dramatically but consistently:

• Posteromedial reach, back and inward: r = 0.605
• Posterolateral reach, back and outward: r = 0.585
• Composite score, the three averaged: r = 0.673

They also ran it against relative strength, meaning strength divided by body weight, which is arguably the fairer comparison between two people of different sizes. The relationships held, a little weaker: 0.658 for the forward reach, 0.537 for the composite.

Across the whole analysis, strength explained somewhere between 21 and 57 percent of the variation in balance performance, depending on which direction and which measure of strength you look at.

Balance and strength "should not be considered separately." That is the authors' own conclusion, and it is the sentence worth carrying out of the paper.

Why it makes sense that they are linked

Reaching your free foot out in front of you is not a passive act of staying upright. It is a slow, controlled single leg squat, performed at the edge of what you can control, while your body mass travels away from your base of support.

Something has to pay for that. The standing leg does. The quadriceps has to lengthen under load and then bring you back, and the further you reach, the more of that it has to do. If the leg does not have the strength to control the descent, you simply stop reaching earlier. Not because your balance system failed, but because your leg ran out of capacity before your balance system was ever properly tested.

That is why the forward reach, the direction that loads the knee most directly, correlated most strongly of all three.

What we take from it in practice

None of the caveats above change the practical point, because the practical point does not depend on the study proving cause. It depends on something simpler: if you only train the balance and never train the leg, you may be working on the wrong half of the problem.

• Test one leg at a time. Both of these measures were unilateral, on purpose. Two legs together will hide a weak side, and the weak side is the one that puts you on the floor. Almost nobody discovers their asymmetry from a two legged exercise.
• If someone wobbles, check whether they are strong. Before adding another proprioception drill, find out whether the standing leg can actually hold a controlled single leg squat. Frequently it cannot, and that is the finding.
• Do not abandon balance work. Strength explained up to 57 percent of the variation, which means at least 43 percent of it came from somewhere else: vision, the vestibular system, the somatosensory input from ankle and foot, plain practice at the task. Both halves are real.
• Use the reach as a number that moves. A reach distance in centimetres is exactly the kind of measurement worth repeating every few weeks. It is objective, it is free, and watching it climb does more for adherence than any amount of encouragement.

The part that matters for later life

This study was done on 21 year olds, and the honest position is that it does not transfer automatically to a 70 year old. But the reason the question is being asked at all is falls, and falls are not a young person's problem.

The mechanism does not obviously change with age. A leg that cannot control a slow descent under load is a leg that cannot catch you when you trip on a kerb. If anything, the argument gets stronger with age, because strength declines with the years while the consequences of losing balance get considerably more expensive.

There is a hormonal layer under that decline, particularly for women through menopause, where muscle is lost and fat redistributes at the same time. Dr de Windt covers that side of it in his piece on muscle and the fat you cannot see.

Linda is in the 70+ division at CrossFit, and what she does there is almost entirely loaded, controlled movement through range. Squats, lunges, carries, presses. Not a wobble board in sight. She did not choose it as a fall prevention program. It just happens to be one.

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